1. Field of the Invention
The present invention is related to a two-stage power supply system; in particular, to a power supply system having a standby power supply mode and a normal power supply mode.
2. Description of Related Art
Due to rapid decrease in global storage of consumptive energy such as coal, crude oil and the like, the problem of consumptive energy waste is becoming a vital issue, resulting in people paying more attention to environmental protection objectives regarding energy savings and green energies. Currently, there are already several countries/areas such as EU, California in US, Korea, and Japan announcing regulations on product standby status (standby power<1 W); meanwhile, at present there are also many home electronic devices introducing power-saving designs therein.
After numerous discussions, tests, and evaluations, many experts consistently agree that to achieve the purpose of power-saving in an electronic product, it is necessary to improve the power consumption of the product in standby mode, since general home electronic devices or common products, e.g. computer screen, television etc., tend not be unplugged while not in use, but are left in standby mode. Therefore, general home electronic devices or common products are frequently in the standby mode, thus wasting substantial amount of power; as a result, the reduction of standby power in electronic products has become one of the most crucial topics now-a-days.
Consequently, it is desirable for the industry to be able to provide a power supply system allowing for energy conservation, and also to enable smooth initiation as a product utilizing the power supply system becomes operative.